Experiments in Fluids最新文献_第6页

The evolution and scaling of controlled flow separation at the inlet of a diverging channel 分流通道入口控制流动分离的演化与尺度

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-07-16 DOI: 10.1007/s00348-025-04073-2

Curtis J. Peterson, Bojan Vukasinovic, Ari Glezer

{"title":"The evolution and scaling of controlled flow separation at the inlet of a diverging channel","authors":"Curtis J. Peterson, Bojan Vukasinovic, Ari Glezer","doi":"10.1007/s00348-025-04073-2","DOIUrl":"10.1007/s00348-025-04073-2","url":null,"abstract":"<div><p>The structure and scaling of flow separation in the adverse pressure gradient at the inlet of a diverging channel are investigated experimentally. The channel flow is diverted from an adjacent uniform flow over a surface through a surface opening, and the separation forms a fluidic constriction across the inlet that severely limits the fraction of the diverted flow. The cross-stream and streamwise scales of the separation domain are progressively diminished by forced streamwise attachment that is effected using a spanwise array of fluidically oscillating control jets placed across the inlet from the main flow. Variable momentum coefficient enables efficient regulation of the diverted fraction of the flow through the diverging channel. The evolution of the flow at separation and within the separation domain is measured using planar PIV and characterized using conditional averaging, spectral analysis, and decomposition methods in the absence and presence of fluidic actuation. Although the streamwise migration of the separation point in the presence of actuation results in changes in the characteristic cross-stream scale of the wall-tangential velocity distributions at separation, the time-averaged velocity distributions in the absence and presence of actuation collapse when scaled by the local vorticity thickness and velocity deficit of the separating shear layer. Proper orthogonal decomposition analysis indicates that despite the energy shift across the flow scales in the presence of actuation, local vorticity modes in the base and controlled flows about separation are remarkably similar, as the uncontrolled flow modes primarily undergo tilting and stretching as separation migrates downstream in the presence of actuation. The global effectiveness of the actuation is assessed by the increased fraction of the diverted flow from the main stream and the accompanying reduction in total pressure losses.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 8","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-025-04073-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145165499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Pocket schlieren: a background-oriented schlieren imaging platform on a smartphone 口袋纹影：智能手机上面向背景的纹影成像平台

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-07-10 DOI: 10.1007/s00348-025-04071-4

Diganta Rabha, Dinesh Saini, Akshay Kumar, Vimod Kumar, Manish Kumar

引用次数: 0

Full-waveform acoustic tomography for fluid temperature and flow 流体温度和流量的全波形声波层析成像。

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-07-08 DOI: 10.1007/s00348-025-04068-z

Lennart Kira, Jerome Noir

{"title":"Full-waveform acoustic tomography for fluid temperature and flow","authors":"Lennart Kira, Jerome Noir","doi":"10.1007/s00348-025-04068-z","DOIUrl":"10.1007/s00348-025-04068-z","url":null,"abstract":"<p>Using the travel time of sound waves advected by a moving carrier medium, acoustic tomography allows to reconstruct temperature and flow fields in opaque fluids without tracers or scattering particles. Reconstruction algorithms are conventionally based on the ray approximation and pose difficulties, especially in enclosed domains: Interferences of early reflections can prevent the assignment of each arrival to the correct ray path. We develop a full-waveform inversion for acoustic tomography in laboratory-scale experiments, perform synthetic tests, and benchmark these with a straight-ray algorithm. Multiple late arrivals of reflected waves are considered in order to increase the quality of the reconstructions when restricted to a sparse transducer array. In addition, the full-waveform algorithm allows to invert simultaneously emitted signals from all sources, decreasing the acquisition time in which a flow must be assumed stationary. These findings make the new method especially interesting for researchers experimenting with enclosed, opaque fluids where no optical imaging is feasible. Furthermore, we envision a potential application of the newly developed method to map flows around objects or complex wall geometries and even multiphase flows.</p>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 8","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12238201/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144607003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design and validation of an experimental set-up to study shock wave propagation in liquid foams 液体泡沫中冲击波传播实验装置的设计与验证

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-07-08 DOI: 10.1007/s00348-025-04070-5

Aymerick Reinders, Julien Le Clanche, Michel Arrigoni, Yann Gregoire, Steven Kerampran, Martin Monloubou

{"title":"Design and validation of an experimental set-up to study shock wave propagation in liquid foams","authors":"Aymerick Reinders, Julien Le Clanche, Michel Arrigoni, Yann Gregoire, Steven Kerampran, Martin Monloubou","doi":"10.1007/s00348-025-04070-5","DOIUrl":"10.1007/s00348-025-04070-5","url":null,"abstract":"<div><p>Liquid foams have shown a significant potential in mitigating pressure waves such as acoustic, shock and blast waves. However, the variety of experimental set-ups in the literature makes it difficult to draw definitive conclusions and compare results from one study to another. This variability can often be attributed to the lack of control over foam parameters, with some, such as bubble size, being undocumented or insufficiently detailed. The present study addresses this issue by developing a set-up that precisely controls critical parameters such as bubble size, liquid fraction, wave Mach number and waveform (sustained shock or blast wave). Pressure waves are generated with a shock tube, and their interaction with foams is analysed in a specifically designed and carefully regulated test section. The versatility of this set-up allows for the exploration of a wide range of wave conditions and foam properties. Preliminary results are presented, which validate our set-up design and its ability to control the relevant parameters for studying pressure wave attenuation.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 8","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145163376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental investigation of a vortex ring in a polymer solution 聚合物溶液中涡旋环的实验研究

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-07-04 DOI: 10.1007/s00348-025-04069-y

Guangwei Liu, Duo Xu

{"title":"Experimental investigation of a vortex ring in a polymer solution","authors":"Guangwei Liu, Duo Xu","doi":"10.1007/s00348-025-04069-y","DOIUrl":"10.1007/s00348-025-04069-y","url":null,"abstract":"<div><p>In this study, we experimentally investigated the kinematic characteristics of solitary vortex rings in polymer solutions. Two distinct experimental configurations are examined: (1) free downstream translation of the vortex ring and (2) vortex ring impingement onto a wall. Under the flow parameters in this study, the vortex ring maintains a laminar state throughout its evolution. Two-dimensional particle image velocimetry measurements of flow velocity fields were performed in the meridional plane of the vortex ring. Compared with its Newtonian fluid counterpart, the polymer solution vortex core exhibits a marked asymmetry in its vorticity distribution, with this disparity becoming more distinct at increased polymer concentrations. Nevertheless, normalized vorticity profiles demonstrate semi-self-similarity across different polymer concentrations. During its free downstream translation, both the translation speed and circulation of the vortex ring exhibit distinct power-law decay characteristics over time. These decay trends can be empirically described by separate scaling relationships. In wall impingement experiments, the azimuthal stretching of a vortex ring in a polymer solution is suppressed compared with its Newtonian counterpart when the inertial effect dominates. After colliding with the wall, a vortex ring in a polymer solution is less prone to develop secondary vortices compared to its Newtonian counterpart.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 7","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145161803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Detecting turbulent patterns in particulate pipe flow by streak-angle visualization 用条纹角可视化方法检测颗粒管流动中的湍流模式

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-07-04 DOI: 10.1007/s00348-025-04065-2

Rishav Raj, Abhiram Thiruthummal, Alban Pothérat

{"title":"Detecting turbulent patterns in particulate pipe flow by streak-angle visualization","authors":"Rishav Raj, Abhiram Thiruthummal, Alban Pothérat","doi":"10.1007/s00348-025-04065-2","DOIUrl":"10.1007/s00348-025-04065-2","url":null,"abstract":"<div><p>Detecting the transition from laminar to turbulent flow in particulate pipe systems remains a complex issue in fluid dynamics, often requiring sophisticated and costly experimental apparatus. This research presents an innovative streak visualization method designed to offer a simple and robust approach to identify transitional turbulent patterns in particulate pipe flows with neutrally buoyant particles. The technique employs a laser arrangement and a low-cost camera setup to capture particle-generated streaks within the fluid, enabling the capture of the temporal evolution of flow patterns. The novelty of the method lies in identifying laminar and turbulent flow patterns from the statistical properties of streak-angle distributions. Validation of the proposed method was conducted through comparison with established techniques like particle image velocimetry (PIV) and pressure drop measurements, confirming its accuracy and reliability. Experiments demonstrate the streak visualization method’s capacity to differentiate between laminar, transitional, and turbulent flow regimes by analysing the standard deviation of streak angles. The method is applicable across a wide range of particle concentrations, as long as the statistical distributions of laminar and turbulent patterns differ, making it versatile where other methods may face limitations. Furthermore, this technique enables us to identify a critical Reynolds number using the Kullback–Leibler divergence built on the statistical distribution of streak angles, which is consistent with previous studies. This streak visualization method offers potential for analysing particulate pipe flows in both laboratory environments and specific industrial scenarios, especially when the fluid is transparent and particles are either naturally occurring or added as tracers.\u0000</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 7","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145161805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Volumetric study of particle-wake interactions based on free falling finite particles 基于自由落体有限粒子的粒子-尾迹相互作用体积研究。

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-06-29 DOI: 10.1007/s00348-025-04066-1

Yi Hui Tee, James R. Dawson, R. Jason Hearst

{"title":"Volumetric study of particle-wake interactions based on free falling finite particles","authors":"Yi Hui Tee, James R. Dawson, R. Jason Hearst","doi":"10.1007/s00348-025-04066-1","DOIUrl":"10.1007/s00348-025-04066-1","url":null,"abstract":"<div><p>Research on free falling particles has predominantly focused on wake dynamics and vortex shedding of individual particles in quiescent flow. However, when these particles fall collectively, the wakes of neighboring particles alter the flow fields. To investigate how the settling and wake dynamics of particles are affected by the wakes of other settling particles, we conducted volumetric experiments using the Shake-The-Box technique. Negatively buoyant 12 mm particles of four different geometries (sphere, flat cuboid, circular, and square cylinders) were first released individually into quiescent water. Subsequently, the particles were released individually into the bulk wakes of 20 monodisperse particles. Using four high-speed cameras and LEDs, we simultaneously captured both 3D particle and fluid motions in the terminal velocity regime. The imaging domain measured 90 mm × 90 mm × 40 mm. Our results show that all trailing particles settling through the bulk wakes gain additional downward momentum from the turbulent wakes, causing them to fall faster than in quiescent flow. However, when the induced velocity of the preceding wakes is subtracted, the relative settling velocity was found to be essentially the same as the particle falling in quiescent fluid. Upstream of the particle, the vortices in the bulk wake interact with the developing shear layer along the particle. The wake downstream of the trailing particle also appears more chaotic than that in quiescent flow.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 7","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12206675/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144537669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Escaping the lab: advances in large-scale particle tracking using natural light and uncrewed aerial vehicles 逃离实验室：利用自然光和无人驾驶飞行器进行大规模粒子跟踪的进展

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-06-28 DOI: 10.1007/s00348-025-04067-0

Robin Leister, David E. Rival

{"title":"Escaping the lab: advances in large-scale particle tracking using natural light and uncrewed aerial vehicles","authors":"Robin Leister, David E. Rival","doi":"10.1007/s00348-025-04067-0","DOIUrl":"10.1007/s00348-025-04067-0","url":null,"abstract":"<div><p>Here we explore the potential of the glare-point particle tracking (GPPT) technique for realistic field-scale measurements. We make use of a commercially available, drone-based camera to extract three-dimensional information under natural light conditions. Air-filled soap bubbles on the order of centimeters are used as seeding tracers. In the current tests, the suitability of the portable setup has been demonstrated for volumes up to <span>(163,)</span> m<span>(^3)</span>. The frame-to-frame camera movement, caused by slight adjustments of the drone flying outdoors, could be quantified and corrected via an image-based approach. Both limits introduced through the larger tracer size and uncertainty caused by the glare-point approach are discussed accordingly. Furthermore, based on the fixed magnification of the drone camera, the limit in drone operation can be determined when the two most dominant, bubble-based glare points collapse onto one, which was observed well above a height of <span>(10,)</span>m. Finally, a turbulent free jet, exiting from a square-shaped nozzle with edge length <span>(0.3,)</span> m, served as an exemplary test case. Tracks emerging at the jet exit all the way to <span>(10,)</span> m downstream of the nozzle were successfully reconstructed in three dimensions. Lagrangian properties, such as flow acceleration, as well as pathline curvature at the integral length scale, were resolved in the large turbulent jet. This sparse yet accurate Lagrangian data over a large physical volume demonstrates insights into turbulent mixing processes at the integral length well beyond current Eulerian-based descriptions.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 7","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-025-04067-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145171263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A combined intensity and lifetime-based laser-induced fluorescence technique (i-(tau)LIF) with dye-doped nanobeads tracer for dissolved oxygen imaging below the water surface 结合强度和寿命为基础的激光诱导荧光技术（i- (tau) LIF）与染料掺杂纳米颗粒示踪剂在水面下的溶解氧成像

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-06-27 DOI: 10.1007/s00348-025-04062-5

E. Murniati, A. Philippe, O. Eiff, H. Herlina

{"title":"A combined intensity and lifetime-based laser-induced fluorescence technique (i-(tau)LIF) with dye-doped nanobeads tracer for dissolved oxygen imaging below the water surface","authors":"E. Murniati, A. Philippe, O. Eiff, H. Herlina","doi":"10.1007/s00348-025-04062-5","DOIUrl":"10.1007/s00348-025-04062-5","url":null,"abstract":"<p>The interfacial transfer process of atmospheric gases, such as oxygen, in a turbulent flow environment is characterized by a very thin concentration boundary layer with a highly dynamic concentration distribution further below the water surface. In order to capture such small-scale details at high time and spatial resolutions, a combined intensity and lifetime-based laser-induced fluorescence technique (i-<span>(tau)</span>LIF) is presented. The combined method allows to use the iLIF method to obtain concentration images, while concurrently, one or more in situ benchmark data points are obtained non-intrusively using the <span>(tau)</span>LIF method, which enables the reconstruction of the absolute (intensity to concentration) iLIF calibration curve from the generally valid normalized iLIF calibration curve. An accurate prediction of the benchmark points is possible, provided their values lie in the lower range of the oxygen concentration. The performance of the combined i-<span>(tau)</span>LIF system was assessed by conducting experiments of interfacial gas transfer promoted by evaporative surface cooling. It was shown that the system was able to reveal the temporal and spatial variations of the concentration boundary layer as well as the structural developments of the deep-sinking plumes and the small-scale plumes that tend to linger near the surface, which are typically found in evaporative-cooling-induced gas transfer. Quantitative validation tests, including a one-to-one comparison of the i-<span>(tau)</span>LIF results with microsensor measurements, yielded very good agreement. The high spatial resolution of the system allowed direct quantification of instantaneous concentration profiles and, hence, the estimation of the instantaneous gas transfer velocity.</p>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 7","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-025-04062-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145170338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development of UAV-based system for simultaneous wind and particle measurements in the atmospheric boundary layer 基于无人机的大气边界层风和粒子同步测量系统的研制

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-06-24 DOI: 10.1007/s00348-025-04064-3

Xiaofei Zhang, Biaosheng Luo, Yixun Liu, Jiaqi Li, Tingwei Liang, Jiarong Hong, Cheng Li

{"title":"Development of UAV-based system for simultaneous wind and particle measurements in the atmospheric boundary layer","authors":"Xiaofei Zhang, Biaosheng Luo, Yixun Liu, Jiaqi Li, Tingwei Liang, Jiarong Hong, Cheng Li","doi":"10.1007/s00348-025-04064-3","DOIUrl":"10.1007/s00348-025-04064-3","url":null,"abstract":"<div><p>This study introduces a novel UAV-based platform for simultaneous wind and particle measurements within the atmospheric boundary layer. By integrating a full-scale sonic anemometer with a multi-resolution digital in-line holography (MRDIH) system, the UAV system captures three-dimensional wind vectors and particle size distributions—ranging from micrometer-scale aerosols to millimeter-sized particles—in real time. A customized hexacopter, equipped with GNSS/RTK/IMU navigation and flight control, enables synchronized data acquisition under varying flight conditions. To ensure accuracy, both time-domain and frequency-domain correction methods are employed to compensate for rotor-induced disturbances, yielding wind measurements that align closely with those from a fixed reference anemometer. Field campaigns validate the system’s ability to resolve turbulence statistics, such as energy spectra and dissipation rates, while DIH measurements demonstrate robust particle sizing in both near-surface and elevated cloud environments. The resulting data provide new insights into wind-particle interactions, including droplet dynamics within clouds and the turbulence-driven particle dispersion. Overall, this UAV platform addresses critical gaps in atmospheric measurements and can be readily adapted for diverse applications, including wind energy site assessment, air-quality monitoring, and fundamental research in dispersed multiphase flows. Future efforts will extend its operational envelope to extreme conditions and integrate refined data-assimilation techniques to further enhance measurement fidelity.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 7","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0